ascorbic acid as a substitute for metol and hydroquinone

RalphLambrecht · Feb 1, 2012

how woul oneuse ascorbic acid as a substitute for metol and hydroquinone?

analog what is that? · Feb 1, 2012

General info says that ut can replace one, but ot the other, in respect to its chemistry.....
Metol forms a superadditive pair with Hydroquinone
Phenidone forms a superadditive pair with Hydroquinone
Phenidone forms a superadditive pair with Ascorbic acid

analog what is that? · Feb 1, 2012

And phenidone with sodium ascorbate is a powerful pair......

What you should be looking for is a substitute for phenidone available in the mall, other than coffe.
I suggest looking at common thea.

Rudeofus · Feb 1, 2012

Ralph,

the unblinking eye website has a few articles about superadditivity and ascorbate developers: this one describes how developers work in general and which compounds are used. This one describes superadditivity, and here the merits of ascorbate are discussed. Also look for relevant postings here on APUG for extra info, e.g. in (there was a url link here which no longer exists).

analog what is that? · Feb 1, 2012

That is true Michael, I'm a chemist and can testify that they (we) didn't learn squat about this in school, neither on fixers and what takes place, just two simple formulas on each respectively, and 5 minutes talk of general principles in all those years!
Reading a few threads here on the subject and subtracting some of the tallest claims you can learn more about the subject in a couple days....

Gerald C Koch · Feb 2, 2012

The similarity between hydroquinone and ascorbic acid is only superficial. Their actions in developers is quit different. Any MQ or PQ developer must be modified when substituting ascorbic acid or sodium ascorbate.

nworth · Feb 3, 2012

I'm not sure about superadditivity between metol and ascorbic acid, but the combination deserves some attention. I experimented with them in a couple of print developers, and I found the results quite rewarding. Normally, ascorbic acid and PC combinations produce rather harsh print developers, with inferior tone. But metol seems to moderate things while still maintaining the necessary contrast. I have made at least one quite good MC cold tone print developer.

RalphLambrecht · Feb 3, 2012

analog what is that? said:
That is true Michael, I'm a chemist and can testify that they (we) didn't learn squat about this in school, neither on fixers and what takes place, just two simple formulas on each respectively, and 5 minutes talk of general principles in all those years!
Reading a few threads here on the subject and subtracting some of the tallest claims you can learn more about the subject in a couple days....

let'd try it:
are you willing to To shareshare the fo the formularmula?

analog what is that? · Feb 3, 2012

Naaaa, you have to wade through all the threads like everyone else, it is about sharing you know, not like in a workplace, ordering those below on the corporate ladder around!

Alan Johnson · Feb 3, 2012

There is a great number of metol-hydroquinone (MQ) formulae.
As far as I know none of the solvent type high sulfite MQ developers have been reformulated as metol-ascorbate developers,though there are some phenidone-ascorbate solvent developers,eg DS-10,E-76,Mytol and the proprietary Xtol and Fomadon Excel.

Two metol-ascorbate acutance developers were detailed by Ryuji Suzuki:
DS-2
http://www.flickr.com/photos/esfotos/sets/72157628018881340/
and DS-12 which gives similar results but contains also ingredients intended to reduce the rate of atmospheric oxidation.
In Ilfosol 3 the ingredients are not disclosed but if it is like Ilfosol S it would be an ascorbate acutance developer.

RalphLambrecht · Feb 4, 2012

analog what is that? said:
Naaaa, you have to wade through all the threads like everyone else, it is about sharing you know, not like in a workplace, ordering those below on the corporate ladder around!

too bad. did the other guy get the promotion again?he was less qualified too snd had less years with the compny. try kissing some sorpor

Ian Grant · Feb 4, 2012

Alan Johnson said:
There is a great number of metol-hydroquinone (MQ) formulae.
As far as I know none of the solvent type high sulfite MQ developers have been reformulated as metol-ascorbate developers,though there are some phenidone-ascorbate solvent developers,eg DS-10,E-76,Mytol and the proprietary Xtol and Fomadon Excel.

There were Metol/Ascorbic acid and Phenidone/Ascorbic acid developers published in Patents etc in the late 1950's, it's likely it's one of these Patents that prevented Kodak and others from making a commercial Ascorbic acid fine grain develoer until its expiry which would have been shortly before the release of Xtol.

Ideally he Ascorbic acid needs to be neutralised with Hydroxide (or carbonate).

So if you started with a simple substitition in say D76/ID-11 then you'd need to add Ascorbic acid in place of Hyrdroquinone (start with 10g) and Sodium or Potassium Hyroxide in 1:1 proportion based on their respective MWs, increasing the buffering and taking care that the pH is kept around 8.5. A touch of Metabisulphite can be used to bring it down.

However that's just a staring point, further work would be needed to improve the developer.

Chris Patton's E76 uses 0.2g Phenidone in place of 2g Metol, increases the Borax to 10g and substitutes 8g Acorbic acid in place of Hydroquinone (compared to D76).

Ian

RalphLambrecht · Feb 6, 2012

yhanks ian. that's what i needed

Ryuji · Feb 6, 2012

Alan Johnson said:
There is a great number of metol-hydroquinone (MQ) formulae.
As far as I know none of the solvent type high sulfite MQ developers have been reformulated as metol-ascorbate developers,though there are some phenidone-ascorbate solvent developers,eg DS-10,E-76,Mytol and the proprietary Xtol and Fomadon Excel.

I don't know where you looked, but DS-1 and prior to that, what I tentatively called "D-76Ad" because it was an ascorbate version of buffered D-76 called D-76d.

However, after testing them and Dimezone versions for years, I ditched the Metol versions, as Dimezone versions are uniformly superior and I don't see a reason to go back to Metol. If anyone wants to buy ALL of my Metol stocks I'd be glad to sell them.

Alan Johnson · Feb 7, 2012

Well they seem interesting for the record if you have done the work and think the dimezone version better.
D-76Ad:
http://greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=007NU3
DS-1:
http://www.film-and-darkroom-user.org.uk/forum/showthread.php?t=1546

They appear to be identical:
Water@20-30C........................750ml (add a pinch of sulfite to this)
Metol.........................................2g
Ascorbic Acid..............................5g
Borax Decahydrate.......................12g
Sodium Sulfite............................100g
Water to make..............................1L
The pH is not given.

Ryuji · Feb 8, 2012

Alan Johnson said:
Well they seem interesting for the record if you have done the work and think the dimezone version better.
D-76Ad:
http://greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=007NU3
DS-1:
http://www.film-and-darkroom-user.org.uk/forum/showthread.php?t=1546

They appear to be identical:
Water@20-30C........................750ml (add a pinch of sulfite to this)
Metol.........................................2g
Ascorbic Acid..............................5g
Borax Decahydrate.......................12g
Sodium Sulfite............................100g
Water to make..............................1L
The pH is not given.

You could start with DS-10 and reduce or remove boric acid to adjust the pH to 8.5 and that is probably close to what you are looking for, as a starting point. The resulting formula is more polished than what's above, though, because of my extra work into stabilizing ascorbate developers. One issue with pH of 8.5 is slightly higher fog, which could be a bit annoying with some films. If that is a problem, a simple solution is to use the developer diluted and not worry about bromide. That's what I'd do if I were to design the developer for my own use, at least with the films I am most familiar with.

Keith Tapscott. · Feb 8, 2012

Ryuji said:
I don't know where you looked, but DS-1 and prior to that, what I tentatively called "D-76Ad" because it was an ascorbate version of buffered D-76 called D-76d.

However, after testing them and Dimezone versions for years, I ditched the Metol versions, as Dimezone versions are uniformly superior and I don't see a reason to go back to Metol. If anyone wants to buy ALL of my Metol stocks I'd be glad to sell them.

If you lived in the UK, then I might have been interested.

Tronds · Feb 8, 2012

Ryuji;1298471 If anyone wants to buy ALL of my Metol stocks I'd be glad to sell them.[/QUOTE said:
It depends on amount and price.
I have plenty of both Dimezone-s and Phenidone but other photochemicals are always of interest.

Ryuji · Feb 8, 2012

I have about 300g total from two sources (two separate jars). One slightly less than 250g, another around 60g. If you're serious please email me directly.

Tronds · Feb 8, 2012

Ryuji said:
I have about 300g total from two sources (two separate jars). One slightly less than 250g, another around 60g. If you're serious please email me directly.

I have sent you a PM earlier, but got no answer.
Reading the comment you wrote in another thread, I think I just drop this. I don't want to do any business with you.

Metol is sold other places so I have no problem getting it.

RalphLambrecht · Mar 8, 2012

Gerald C Koch said:
The similarity between hydroquinone and ascorbic acid is only superficial. Their actions in developers is quit different. Any MQ or PQ developer must be modified when substituting ascorbic acid or sodium ascorbate.

gerald, i think you and michael are quite right that a sustitution is not as simple as i had hoped. so far, from what i'vr read, i conclude a starting point is :replace metol wiyh 1%of its weight with phenidoneand replace hydroqinone with 8/5 of its eight with sscorbic acid. i wil try this with d76 first(i think it's called e76),and report the otcome.thamks for the commrntts so far.

piu58 · Mar 9, 2012

> :replace metol wiyh 1%of its weight with phenidoneand replace hydroqinone with 8/5 of its eight ...

Dear Ralph,

please note that such developers have some disadvantages against the older formulae. Phenidone is very active and need to be in solution in a very small amount. Therefore it is not able to develop a film by itself, the amount is to low. The redox system is strongly necessary. (In copmparision: Metol alone will develop you film, even if the HQ is nearly dead).

The small amount of Phenidone will not lead to any discoloration of oxydized developer. Citrix acid's products are colorless too.

This leads to:
- You don't see if the developer is aged, no brownish color.
- Because of the high activity of Phenidone the developer will work with the smallest amount of the redox system (citrate). Some days later, when this small amount is exhausted, the developer will not develop anymore. The amount of Phenidione is to small for a "slow dying".

Athiril · Mar 9, 2012

Ascorbates will regenerate phenidone, you can have a pH where ascorbate won't develop, but with phenidone regenerating it'll again be more active than without it.

RalphLambrecht · Mar 9, 2012

athirl,

do you have a working formula, you can recommend?

RalphLambrecht · Mar 15, 2012

i decided to try the e76 formula from Chris patten.

ascorbic acid as a substitute for metol and hydroquinone

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